Image processing device, image processing method and image processing system

ABSTRACT

An image processing device and an image processing method that performs image interpretation as fast as possible, without oversight by an interactive operation, when performing the image interpretation of a large amount of volume data in which an interest region is set in advance are provided. The image processing device that generates a two-dimensional image from a captured three-dimensional image and displays the generated two-dimensional image receives an input signal relating to primary display control information including a speed of a display control input of the two-dimensional image, calculates the primary display control information from the input signal, calculates secondary display control information including a display speed of the two-dimensional image based on information of an interest region and the primary display control information, and sequentially generates the two-dimensional images based on the secondary display control information and displays the generated two-dimensional image.

TECHNICAL FIELD

The present invention relates to an image processing device and an imageprocessing method for generating a two-dimensional image from athree-dimensional image and displaying the image.

BACKGROUND ART

In a diagnosis in which a medical image inspection apparatus representedby an X-ray computed tomography (X-ray CT) apparatus, a magneticresonance imaging (MRI) apparatus or the like is used, it is common thata captured three-dimensional medical image (hereinafter also referred toas “volume data”) is reconstructed as a continuous two-dimensional imageand then image interpretation is performed.

There is a trend of imaging apparatuses becoming more sophisticatedevery year and the data size per volume data tending to increase. Inaddition, especially in a CT apparatus, imaging of high-quality volumedata using low doses has become possible and imaging opportunities havealso tended to increase. Therefore, a burden on a doctor or an engineerwho performs the image interpretation for this large amount of medicalvolume data is very high.

In order to mitigate the burden, there is growing a need for the use ofcomputer aided detection, or computer aided diagnosis (CAD). CAD refersto a system and a technique which perform quantification and analysis ofimage information with a computer and an information processingtechnique based on a computer.

A typical function of CAD includes a function which automaticallyextracts a high suspicion disease region using an image processingtechnology from values and a distribution of voxels of the medicalvolume data as target data and then provides the high suspicion diseaseregion as an interest region, for example. However, CAD performs onlysupport regarding the diagnosis and thus confirmation of a doctor isrequired upon the diagnosis including determination of whether or notthe interest region falls on a disease region.

In a case of performing the image interpretation of the volume data inwhich the interest region is set in advance by the CAD or the like, asmatters required of a doctor or an engineer to confirm, there areconfirmation whether or not the interest region is correctly set to thedisease region while looking at the interest region set in advance andconfirmation whether or not there is no disease region while looking atthe area where the interest region has not been set. It is necessary toconfirm the regions without oversights, as fast as possible.

In the related art, when performing the image interpretation of a largeamount of volume data in which the interest region is set in advance, atechnique of performing the interpretation without oversights, as fastas possible has been proposed.

For example, in PTL 1, an apparatus and a program which allow in-depthimage interpretation by delaying a display speed of the image datagenerated in an image section intersecting with the interest region thana display speed of the image data generated in other image sections areproposed.

CITATION LIST Patent Literature

PTL 1: JP-A-2013-85622

SUMMARY OF INVENTION Technical Problem

In the technique disclosed in PTL 1, there is a problem that, during theimage interpretation, since a display speed automatically decreases to adelayed speed, a portion which is considered to be unnecessary by anoperator is also displayed at a low speed and as a result, the entireimage interpretation time is increased, and since the imageinterpretation is an operation of which interactivity is low, stress ofthe operator increases.

An object of the present invention is to provide an image processingdevice and an image processing method which can perform imageinterpretation with less oversight, as fast as possible, by aninteractive operation.

Solution to Problem

An image processing device according to the present invention includes astorage unit that stores an image database relating to athree-dimensional image; an input receiving unit that receives an inputsignal according to an operation of a user terminal; a primary displaycontrol information calculating unit that calculates primary displaycontrol information including a speed of the received input signal; asecondary display control information calculating unit that calculatessecondary display control information including a display speed of atwo-dimensional image which is generated from the three-dimensionalimage based on information of an interest region determined as a highsuspicion disease region in the three-dimensional image and thecalculated primary display control information; and an image generationand transmission unit that sequentially generates the two-dimensionalimages and transmits the generated two-dimensional image to the userterminal, based on the calculated secondary display control information.

Advantageous Effects of Invention

According to the present invention, image interpretation can beperformed as fast as possible, with less oversight by an interactiveoperation of an input unit.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view illustrating a configuration of an image processingsystem according to Example 1.

FIG. 2 is a flow chart illustrating an example of calculation process ofdisplay control information.

FIG. 3 is a view illustrating an example of a process calculating aninput speed from input.

FIG. 4 is a view illustrating a coordinate system of an imaging targetbody.

FIG. 5 is a view illustrating an interest degree setting table in whichthe degree of interest with respect to section positions is set,according to Example 2.

FIG. 6 is a view illustrating a time interval setting table in whichtime intervals between input times and display times are set.

FIG. 7 is a view illustrating relationships between the degrees ofinterest when crossing interest regions and the time intervals frominput to display.

FIG. 8 is a view illustrating images which display two-dimensional imagedisplay timing, in a case where the time intervals from input to displayare changed.

FIG. 9 is a view illustrating a section interval setting table in whichsection intervals are set with respect to change flags displaying thedegree of interest of the interest regions, the input speeds and ahistory thereof, according to Example 3.

FIG. 10 is a view explaining a viewpoint angle and a viewpoint positionusing a three-dimensional coordinate system when creating athree-dimensional visualization image of volume data, according toExample 4.

FIG. 11 is a view illustrating the interest degree setting table inwhich the degree of interest with respect to the viewpoint angle whencreating the three-dimensional visualization image is set.

FIG. 12 is a view illustrating the interest degree setting table inwhich the degree of interest with respect to a three-dimensionalposition of the volume data is set.

DESCRIPTION OF EMBODIMENTS

Hereinafter, four examples will be described using the drawings.

EXAMPLE 1

In the present example, an example of an image processing devicedetermining secondary display control information according to primarydisplay control information will be described. Here, the primary displaycontrol information is a speed of a pulse input signal detecting wheelrotation of a mouse during image interpretation by scrolling atwo-dimensional image, for example and is intermediately generatedinformation which is a basis for calculating the secondary displaycontrol information for finally displaying the two-dimensional image ona display unit or a display device. The information will be describedbelow in detail.

In addition, the secondary display control information is a timeinterval (display delay time) from an input time of the input signal toa two-dimensional image display time, for example. The information willbe described below in detail.

FIG. 1 is a view illustrating a configuration of an image processingsystem according to the present example. As illustrated in FIG. 1, thepresent system includes an image processing device 100 which generatesthe two-dimensional image by performing image processing with respect toa three-dimensional image, an image data storage server 200 which storesinterest region information such as an imaged and reconstructedthree-dimensional image and a position of an interest region using anX-ray CT apparatus, an MRI apparatus, or the like, a user terminal 300which includes an input unit 320 inputting a processing request to theimage processing device 100 and an image display unit 310 performingdisplay of image data, and a network 400 which connects the imageprocessing device 100, the image data storage server 200, and the userterminal 300 with each other.

The image processing device 100 includes an input receiving unit 10which receives a start signal from the user terminal 300, and an inputsignal according to, for example, operation of movement and wheelrotation of a mouse in the input unit 320 of the user terminal 300, aprimary display control information calculating unit 20 which calculatesthe primary display control information, a secondary display controlinformation calculating unit 30 which calculates the secondary displaycontrol information, an image generation and transmission unit 40 whichgenerates the two-dimensional image and transmits the generatedtwo-dimensional image to the image display unit 310 of the user terminal300, an input storage unit 50 which stores the input signal from theinput receiving unit 10, and a display control information storage unit60 which stores the primary display control information and thesecondary display control information.

Here, the primary display control information calculating unit 20calculates the primary display control information such as an inputspeed, for example, from the input signal obtained from the inputreceiving unit 10. In addition, the secondary display controlinformation calculating unit 30 calculates the secondary display controlinformation such as a display speed, for example, from the primarydisplay control information obtained from the primary display controlinformation calculating unit 20 and the information of the interestregion and the three-dimensional image obtained from the image datastorage server 200.

Next, using FIG. 2, a flow of processing when the secondary displaycontrol information is determined corresponding to the primary displaycontrol information is explained.

The input receiving unit 10 of the image processing device 100 startsimage processing by receiving the start signal as an input from theinput unit 320 of the user terminal 300 (S101). The input receiving unit10 confirms the presence or the absence of the input from the input unit320 of the user terminal 300 (S102). In a case where there is no input,the processing is terminated (S103).

In a case where there is the input, the primary display controlinformation such as the input speed, for example, is calculated from acurrent input obtained from the input receiving unit 10 and inputhistory obtained from the input storage unit 50 in the primary displaycontrol information calculating unit 20 (S104), and current inputinformation is stored in the input storage unit 50 (S105).

Next, the secondary display control information including the displayspeed is calculated from history of the primary display controlinformation obtained from the primary display control informationcalculating unit 20, the information of the volume data(three-dimensional medical image) and the information of the interestregion obtained from the image data storage server 200, and thesecondary display control information including a section position of atwo-dimensional section image obtained from the display controlinformation storage unit 60 in the secondary display control informationcalculating unit 30 (S106). A current primary display controlinformation and a current secondary display control information arestored in the display control information storage unit 60 (S107).

Finally, a display image is generated or is acquired from thethree-dimensional image or a plurality of two-dimensional images storedin the image data storage server 200, using the secondary displaycontrol information including the display speed and a section positionof the two-dimensional section image obtained from the secondary displaycontrol information calculating unit 30 in the image generation andtransmission unit 40. The two-dimensional image displayed by adetermined display speed is transmitted to the image display unit 310 ofthe user terminal 300 (S108) and then the processing returns to S102 torepeat the same processing.

In addition, execution after the second time of S102 is not necessary tobe held until the end of S108 and if only S105 is terminated, the nextflow from S102 may be started. Here, a case where the input receivingunit 10 receives the input according to a screen scrolling operation ofthe continuous two-dimensional images, as continuous inputs will bedescribed.

In order to describe the continuous inputs, it is considered a casewhere the input receiving unit 10 receives a plurality of inputs in anorder of i [0] , i [1] , i [2] , . . . Here, the inputs i [0] , i [1] ,i [2] , . . . are inputs from the input unit of the same user terminaland thus are different from each other only in an input time. Here, acase where a state of the input time difference between i[0] and i[1]and the input time difference between i [1] and i [2] being less thand_th is continued, i [0] , i [1] , i [2] , . . . are determined as thecontinuous inputs and if the input time of the input received by theinput receiving unit 10 is a time elapsed by d_th or more from the inputtime of the input received previously, it is determined that thecontinuous inputs are terminated.

Here, for example, in the input unit 320 of the user terminal 300, in acase where the wheel of the mouse is rotated or a curser movement isperformed on the screen using the mouse, or a case where an operation bytracing with a finger or the like is performed using a touch panel, adiameter of the wheel or the screen size of the touch panel or displayis limited and there is a limit of resolution of the input and even ifthe continuous inputs are performed, the continuous inputs areinterrupted at regular interval. Even in such a case, the interruptionof the input can be dealt by setting d_th larger in the above example.

Here, an example of calculating the primary display control informationat S104 in a case where the input is received as the continuous inputswill be described. Usually, the speed of the continuous inputs can beconsidered to be equivalent to an image display speed which is desiredat the operation point in time by a user, since the two-dimensionalimage display is performed according to the input such as the wheelrotation of the mouse. Here, it is described that the input time of theinput is used and the primary display control input information is aspeed of the continuous inputs. For example, in a case where the inputtime of input i [n] at certain point in time is t[n] , in the primarydisplay control information calculating unit 20, the input time t[n−1]of the previous input i [n−1] is used, the input speed v[n]=1/(t[n]−t[n−1]) is calculated and then it is output as the primarydisplay control information corresponding to i [n].

Next, using FIG. 3, a case where the input receiving unit 10 receivesintermittent continuous inputs will be described. FIG. 3 illustratesrelationships between the input times t[0] , t[1], . . . correspondingto the inputs i [0] , i [1] , . . . and the input speeds. Here, each ofthe input speeds v[1], v[2], . . . is respectively calculated asv[1]=1/(t[1]−t[0]), v[2]=1/(t[2]−t[1]), . . . .

The intermittent continuous inputs are assumed inputs of which thecontinuous inputs of which the value of input speeds of each input v[1]to v[4] is high and the variation of these input speeds is small, suchas i[1] to i [4] , and an input after the continuous inputs areinterrupted, of which the input speed v[5] is low to a certain extentsuch as i [5] , are repeated in order, for example. Here, the continuousinput number such as i [1] to i [4] is referred to as a continuous inputnumber ni, the speed while the continuous inputs continue such as t[0]to t[4] is referred to as a continuous input speed vc, and the speedsuch as v[5] while the input is interrupted is referred to as a blankspeed vb. Here, vc[1]=1/(t[4]−t[0]), vb [1]=v [5] is calculated.

In this case, in the primary display control information calculatingunit 20, each of the continuous input speed vc, the blank speed vb, orthe continuous input number ni can be used as the primary displaycontrol information. In addition, as information used for calculation ofthe primary display control information calculating unit 20, theinformation is not necessarily the input time of the each input at theinput unit 320 of the user terminal 300 and may be input receiving timeor the input number per unit time in the input receiving unit, forexample. In a case of using the input number per unit time, S104 isperformed at a time interval fixed in advance. The primary displaycontrol information which is calculated at S104 is the input number perunit time.

Here, in FIG. 4, a coordinate system of a three-dimensional coordinateusing in the following examples is illustrated. The volume data used inthe examples sets each axis corresponding to a human body which isimaged since it is assumed that the volume data is obtained by imagingthe human body. Here, in a state where a subject has arms put down,faces forward and stands upright, a direction from the right hand to theleft hand is referred to as an X-axis, a direction from front to back isreferred to as a Y-axis and a direction from the foot to the head isreferred to as a Z-axis.

EXAMPLE 2

The secondary display control information calculated in the secondarydisplay control information calculating unit 30 includes a sectionposition in a case where the two-dimensional section image is generatedfrom the volume data, a viewpoint position in a case where thethree-dimensional visualization image is generated, or athree-dimensional reconfiguration resolution in a case where thethree-dimensional visualization image is generated, or the like, forexample, in addition to the display speed in a case where thetwo-dimensional section image or the three-dimensional visualizationimage are displayed.

In this example, in a case where the two-dimensional image generated inthe image generation and transmission unit 40 is a continuous sectionalview of a case where the volume data is cut in a plurality of parallelplanes which are perpendicular to certain axis and are continuous on theaxis, as an example of the secondary display control informationdetermined according to the primary display control information, thetime interval (display delay time) between the input times of inputs andthe display time of the two-dimensional image is included. Hereinafter,a method for determining the time interval will be described.

Here, the continuous section is a plane which is perpendicular to theZ-axis and a Z coordinate thereof is s_0, s_1, . . . s-e. Here, s_0 ands_e indicate the section positions of both ends of the continuoustwo-dimensional section image which is generated from thethree-dimensional volume data. In addition, the interval of each planeis a fixed value dis. The two-dimensional section image is reconstructedin advance as image [s_0] to image [s_e] so that one image correspondsto each section position, and is stored in the image data storage server200.

In addition, as the interest region information, information on whichthe degree of interest is uniquely determined with respect to thesection position in advance is stored in the image data storage server200. Here, as an example thereof, the interest degree setting table isillustrated in FIG. 5. In FIG. 5, d_b is a higher value than d_a. Inother words, FIG. 5 illustrates a case where the interest region betweenthe section position s_r0 and the section position s_r1 is included.

In addition, here, one of the primary display control information is theinput speed v which is calculated from information of the input and thesecondary display control information calculating unit 30 uses a changeflag f as one of the primary display control information. The changeflag f indicates change history of the primary display controlinformation and here while displaying an inside of the interest regionhaving the same degrees of interest, the flag counts the number of timesof the input speed v falling below a threshold v_th. Here, the thresholdv_th is to detect the change of the input speed. Accordingly, v_th isdetermined according to the input speed so far, and for example, theprevious input speed is v_th or an average of the input speed until theprevious input is v_th.

The display control information storage unit 60 holds information inwhich the time interval between the input time and the display time isuniquely determined by the degree of interest, the input speed v whichis the primary display control information, and the change flag f, inadvance. A time interval setting table which is an example of theinformation is illustrated in FIG. 6. A case where ti a is very smallvalue and ti_b is a value which is greater than ti_a to the extent thata difference between the display speeds due to the difference betweenthe time intervals can be visually recognized is illustrated in FIG. 6.

In a case where the degree of interest is d_b, the input speed v isequal to or greater than v_th, and f is less than f_th, the intervalbetween the input time and the output time is increased to ti_b, and ina case of combinations in addition to this, the interval between theinput time and the output time is decreased, as illustrated in FIG. 6.However, in a case where the change flag f is equal to or greater thanthe predetermined threshold f_th, that is, in a case where the number oftimes of the input speed v being less than v_th in the interest regionis equal to or greater than f_th, the time interval is decreased to afixed value ti_a, even in any case of FIG. 6.

A flow of a specific processing will be described. First, an imageimage[s[n]] is displayed in the image display unit 310 of the userterminal 300, and the input receiving unit 10 is in a state where i[n+1] which is one of the continuous inputs is received. As informationcorresponding to inputs i[0], . . . i[n] which is received so far atthis point in time, a time t[0], . . . t[n] is stored in the inputstorage unit 50, and as the secondary display control informationcorresponding to the previous input i[n], the section position ofdisplay two-dimensional image s[n], and the time interval ti[n] arestored in the display control information storage unit 60.

The input receiving unit 10 receives the input time t[n+1] of thecurrent input from the input unit 320 of the user terminal 300 andstores t[n+1] in the input storage unit 50. Next, the primary displaycontrol information calculating unit calculates the input speedv[n+1]=1/(t[n+1]−t[n]) calculated from t[n+1] and the previous inputtime t[n] and then stores the value in the display control informationstorage unit 60. The secondary display control information calculatingunit 30 determines the time interval ti[n+1] from the current inputspeed v[n+1] and the history obtained from the display controlinformation storage unit 60 and the interest region information obtainedfrom the image data storage server 200.

Here, an example of algorithm of determining the time interval ti[n+1]by the secondary display control information calculating unit 30 will bedescribed below. The previous section position s[n] is acquired and thenext section position s[n+1] is obtained, from the display controlinformation storage unit 60. Here, the section interval has a fixedvalue dis and is s[n+1]=s[n]+dis.

The secondary display control information calculating unit 30 refers tothe interest degree setting table as illustrated in FIG. 5 and thedegree of interest d[n+1] corresponding to the section position s[n+1]is obtained. At this time, in a case where d[n+1] is a value which isdifferent from the degree of interest d[n] corresponding to the sectionposition s[n], the change flag f is initialized to 0.

Next, the secondary display control information calculating unit 30refers to the time interval setting table as illustrated in FIG. 6, thetime interval ti[n+1] herein is obtained from the change flag f, thedegree of interest d[n+1], and the input speed v[n+1], and the currentsection position s[n+1] is stored to the display control informationstorage unit 60. At this time, in a case where the input speed v[n+1]falls below v th, the change flag f becomes f+1.

The image generation and transmission unit 40 acquires thetwo-dimensional image image[s[n+1]] corresponding to the sectionposition s[n+1] from the image data storage server 200 and thentransmits the acquired two-dimensional image image [s[n+1]] to the userterminal 300 and the two-dimensional image image[s[n+1]] is displayed onthe input unit 320 from the input time after the time interval ti[n+1].

Here, a situation in which the interest region is presented byautomatically changing the time interval from ti_a to ti_b, and aninteractive operation is performed will be described. As an example, acase where the input of the continuous control signals of input i[0] toi[5] is provided and the section positions s[0] to s[5] corresponding toeach control signal are provided will be described. Here, in a casewhere s[0] and s[1] are less than s_r0, s[5] is greater than s_r1, ands[2], s[3], and s[4] are equal to or greater than s_r0 and are less thans_r1, that is, s[2] to s{4] are inside the interest region and s[0],s[1], and s[5] are outside the interest region.

In this case, an example of a parameter change of a case where the inputspeeds v[0] to v[2] are equal to or greater than v_th, v[3] is less thanv_th, and the change flag threshold f_th is 1 is illustrated in FIG. 7.In addition, an image of an image display timing corresponding to thechange of the parameter is illustrated in FIG. 8.

Here, since a level of interest is displayed as d_a, that is, a regionwith low interest until the input i[0] to i[1], the time difference tibetween the input time and the output time becomes a very small value asti_a and the display is performed in the form of following-up thecontinuous inputs. Here, a case where the section position has enteredthe interest region is considered. Here, the threshold v_th is slightlysmaller value than an average value of the input speed in a case ofviewing regions other than the interest region (for example, a value ofabout 90% of the input speed average value when viewing the outside ofthe interest region). At the point in time of i [2] , in a case wherethe input is performed with the same degree of the input speed as i [0]and i [1] , since the input speed v[2] is equal to or greater than v_th,the time difference ti between the input time and the output time isincreased to ti_b, and followability with respect to the continuousinputs is automatically decreased. Therefore, it is possible to draw theattention of the user in the case of entering the interest region.

Here, at the point in time of input i [3] , in a case where a userdelays the input speed, the input speed v[3] is less than v_th, the timeinterval returns from ti_b to ti_a, and returns to normal followability.Here, as described above, since v[2] is greater than v th, the changeflag f becomes 1 and thus equals to f_th, until the next display of theinterest region is performed and the change flag f is initialized to 0,the followability is not reduced. This indicates that a scroll displayof high followability becomes possible again because the user noticesthat the section position of the current display two-dimensional imageis in the interest region due to the low follow-up with respect to thecontinuous inputs, and delays an operation controlling a display timingof the continuous two-dimensional image and thus ti is decreased fromti_b to ti_a.

In addition, here, a case where the present technique is used for aclinician to reduce the image interpretation time and decrease detectionomission at a situation in which the image interpretation is performedwhile referring to the interest region set in the CAD system, will beexplained.

The interest region information set by the CAD or the like is not alwaysjust enough information necessary for the user. In other words, in acase where a function detecting the disease suspicion region is used,there is a possibility that detecting of the disease region is failed ora region which is not clinically the disease region is detectedaccording to a detection accuracy thereof. As a specific example ofdetecting a region which is not clinically the disease region, forexample, there is a case where a treatment mark which is made bytreatment in the past or a region where inflammation occurred, but notbecame a disease is detected as the disease suspicion site.

Here, assuming the mouse as the input unit 320 of the user terminal 300,there is a case where scrolling is performed by rotating the wheelthereof and thus the image interpretation is performed by sequentiallyviewing the continuous two-dimensional image which is generated from thethree-dimensional image.

If a technique according to the present invention is used, at the timeof approaching the disease areas that the display two-dimensional imageis automatically detected, the following-up with respect to thescrolling operation is automatically reduced, and the approach to anautomatically detected region can be presented by only with thetwo-dimensional image display region without displaying a thumb nailimage or the like on another region. Here, in a case where the doctornotices the automatically detected region is displayed, thefollowability with respect to the scrolling operation returns to theoriginal followability, by slowing the operation speed of the scrollthan before.

In a case where the approach to the automatically detected region isnoticed by doctor, it is not necessary to perform automatic presentationby the system thereafter. As a result of the automatically detectedregion being confirmed by eyes of the doctor, in a case where it is nota disease suspicion site, a high-speed display is required, and in acase where it is the disease suspicion site, a low-speed display isrequired. The operation thereof can be realized by following thescrolling operation speed of the doctor.

Therefore, high speed image interpretation without stress is possible,by determining whether or not the approach to the automatically detectedregion is noticed by doctor by a change of the scrolling operation speedand returning to the original followability of the scrolling operationspeed.

EXAMPLE 3

In the present example, in the configuration of the image processingsystem illustrated in FIG. 1 and the flow illustrated in FIG. 2, a caseof modifying the section interval of the two-dimensional section imagewhich is reconstructed from the volume data in the secondary displaycontrol information determined according to the primary display controlinformation will be described. In addition, here, in the same manner asin Example 2, as the primary display control information, the inputspeed v calculated from the input information is used, and the secondarydisplay control information calculating unit 30 also holds the changeflag f which counts the number of times of the input speed v fallingbelow the threshold v_th as one of the primary display controlinformation, while displaying the inside of the interest region havingthe same degree of interest.

Here, the display control information storage unit 60 holds in advancethe information on which the section interval is uniquely determinedfrom the degree of interest, the input speed, and the change flag. As anexample of this information, the section interval setting table isillustrated in FIG. 9.

Hereinafter, the flow of the specific processing will be described. Theimage image [s[n] ] is displayed in the image display unit 310 of theuser terminal 300 and the process starts from a state where it isdetermined that the input receiving unit 10 has received the continuousinputs. At this point in time, as the previous information, the inputtimes t[0], . . . t[n] are stored in the input storage unit 50 and thesection position s[n] and the change flag f=0 are stored in the displaycontrol information storage unit 60.

The input receiving unit 10 stores the input time t[n+1] of inputs whichare input from the input unit 320 of the user terminal 300 in the inputstorage unit 50. The primary display control information calculatingunit 20 calculates the input speed v [n+1] and then stores a calculatedinput speed in the display control information storage unit 60. Thesecondary display control information calculating unit 30 determines thesection position s[n+1] from the current input speed v [n+1] obtainedfrom the display control information storage unit 60, the interestregion information obtained from the image data storage server 200, andthe section position s[n] of the previous two-dimensional display imageand the change flag f obtained from the display control informationstorage unit 60.

Here, an example of an algorithm in which the secondary display controlinformation calculating unit 30 determines the section position s[n+1]will be described.

The previous section position s[n] is acquired from the display controlinformation storage unit 60, and s[n]+gm is obtained using apredetermined minimum section interval gm. As the interest regioninformation, information on which the degree of interest is uniquelydetermined with respect to the section position is stored in advance inthe image data storage server 200. The interest degree setting table asillustrated in FIG. 6 as an example is referred and in the calculationof the secondary display control information calculating unit 30, thedegree of interest corresponding to the section position s[n]+gm becomesd[n+1].

Next, the secondary display control information calculating unit 30refers to the section interval setting table (FIG. 9) stored in theimage data storage server 200, determines the section interval g[n+1]from the degree of interest d[n+1] and the input speed v[n+1] ands[n+1]=s[n]+g[n+1] is obtained. Here, the secondary display controlinformation calculating unit 30 again refers to the interest degreesetting table of FIG. 5 and obtains the degree of interest d[n+1]corresponding to s[n+1].

Here, in a case where d[n+1] is a value which is different from thedegree of interest d[n] corresponding to the section position s[n], thechange flag f is initialized to 0. In a case where d[n+1] and d[n] arethe same as each other and in a case where the input speed v[n+1] fallsbelow v_th, the change flag f becomes f+1.

The image generation and transmission unit 40 generates thetwo-dimensional image image [n+1] corresponding to the section positions[n+1] from the volume data which is stored in the image data storageserver 200, transmits the generated two-dimensional image to the userterminal 300, allows the image display unit 310 to display image[s[n+1]] after the time interval ti from the input time t[n+1], andstores the current section position s[n+1] in the display controlinformation storage unit 60.

For example, in a case where s[n] is less than s_r0 and s[n]+gm is equalto or greater than s_r0 and is less than s_r1, the degree of interest isd_b in s[n+1] and the degree of interest is d_a in s[n] , as can be seenfrom FIG. 5. Therefore, when d_b>d_a is considered, once reached s[n+1]from the s[n] , the degree of interest is increased from d_a to d_b, andif v which is equal to or greater than v_th is considered when f is 0,the section interval is changed from g_a to g_b, as can be seen fromFIG. 9. Here, for example, in a case where the value of g_b is set to besmaller than that of g_a, the two-dimensional image of which the sectioninterval is narrower, that is, the two-dimensional section image ofwhich the resolution between sections is high is displayed with respectto s[n+1] in which the degree of interest is high and thus it ispossible to prompt the attention of the user.

EXAMPLE 4

In the present example, in the configuration and the flow described inExample 1, a case where the image generation and transmission unit 40generates the three-dimensional visualization image will be described.

Assuming a plurality of parallel rays passing through the inside of thevolume data, the three-dimensional visualization image is thetwo-dimensional image which processes and generates a voxel valueaccording to certain law along the ray. As representative means forcreating the three-dimensional visualization image, there are a surfacerendering which views a surface of a voxel group having brightness whichis equal to or greater than a fixed threshold in voxels of the volumedata, a volume rendering which expresses also an inside of an object bysetting opacity from the brightness value of the voxel of the inside ofthe volume data and overlapping the value thereof along the ray, an MIPrendering only the maximum brightness by the voxel present on the ray,or the like.

Here, a case where the interest degree information is set by theviewpoint angle will be described. The viewpoint angle will be explainedbelow using FIG. 10.

Certain initial point p_(x_p0, y_p0, z_p0) is set first. In a case wherea center of the volume data is v-c (x_pc, y_pc, z_pc), in a plane planec perpendicular to the Z-axis through v_c, a point which intersects withZ-axis is p_c. p_c can be expressed as a three-dimensional coordinate(x_p0, y_p0, z_pc). Each point p_q on a circumference of a circle whichis obtained by rotating a line segment 1_0 connecting p_c and the centerv_c of the volume data with each other on the plane_c around v_c is aviewpoint position when generating the volume rendering. At this time,an angle between a line segment 1_q connecting p_q and v_c with eachother and the line segment 1_0 is a viewpoint angle a_q.

The interest degree setting table of a case where the degree of interestis set by the viewpoint angle a_q is illustrated in FIG. 11. In thiscase, the two-dimensional image stored in the image data storage server200 or the two-dimensional image generated in the image generation andtransmission unit 40 are three-dimensional visualization imagesimage[p_0] to image[p_2π] viewed from each viewpoint position p_q of acase a_q=0 to 2π.

As an example of the secondary display control information determinedaccording to the primary display control information of a case where thethree-dimensional visualization image becomes the two-dimensional imageat the time of the output, in the same manner as in Example 1, theviewpoint angle, or the time interval between the input time and thedisplay time of a case where the reconstructed three-dimensionalvisualization image is displayed, or ray density or a sampling intervalon the ray when the three-dimensional visualization image isreconstructed can be used. The displayed three-dimensional visualizationimage image [p_0] to image [p_2π] may be created in advance and storedin the image data storage server 200 as described herein or it is alsopossible to create the image each time in the image generation andtransmission unit 40.

In the Examples so far, as the information which indicates the interestregion, as illustrated in FIG. 5, even if the interest degree settingtable is described as an example in which the degree of interest withrespect to the two-dimensional image section position is uniquelydetermined, the information which indicates the interest region is notonly the two-dimensional image section position and the degree ofinterest with respect to the three-dimensional position can be set asthe information, for example. As an example thereof, the interest degreesetting table is described in FIG. 12. Three interest regions areindicated in the example of FIG. 12, the three-dimensional coordinates(x_r0, y_r0, z_r0), (x_r1, y_r1, z_r1), and (x_r2, y_r2, z_r2) indicatethe center positions of the interest regions, respectively and r_r0,r_r1, and r_r2 indicate radiuses of each interest region.

Here, the interest region is a spherical shape and with respect to theregions of three inside portions of a sphere expressed from a center anda radius of the sphere, the degrees of interest are d_0, d_1, and d_2,respectively and with respect to the regions of three outside portionsof the sphere, the degree of interest is d_3.

The present invention is not limited to the above examples and includesvarious modified examples. For example, the examples described above aredescribed in detail in order to make the present invention easy tounderstand, and are not intended to be limited to be necessarilyprovided with all the configurations described. In addition, it ispossible to replace a portion of the configuration of some example withthe configuration of another example and in addition, it is possible toadd the configuration of another example to the configuration of someexample. In addition, with respect to a portion of the configuration ofeach example, it is possible to add, remove, and replace anotherconfiguration.

In Example 1, the image data storage server 200 is configured to beinstalled on the outside portion of the image processing device 100.However, the data stored in the image data storage server 200 may beconfigured to be stored in an inside storage device of the imageprocessing device 100 or a storage unit of the image processing device100 may be configured with the data stored (in the image data storageserver 200 and data stored) in the storage unit of image processingdevice 100.

In addition, the user terminal 300 is configured to be connected to theimage processing device 100 through the network 400. However, the userterminal 300 maybe configured to be directly connected to the imageprocessing device 100.

REFERENCE SIGNS LIST

10: input receiving unit

20: primary display control information calculating unit

30: secondary display control information calculating unit

40: image generation and transmission unit

50: input storage unit

60: display control information storage unit

100: image processing device

200: image data storage server

300: user terminal

1. An image processing device, comprising: a storage unit that stores animage database relating to a three-dimensional image; an input receivingunit that receives an input signal according to an operation of a userterminal; a primary display control information calculating unit thatcalculates primary display control information including a speed of thereceived input signal; a secondary display control informationcalculating unit that calculates secondary display control informationincluding a display speed of a two-dimensional image which is generatedfrom the three-dimensional image based on information of an interestregion determined as a high suspicion disease region in thethree-dimensional image and the calculated primary display controlinformation; and an image generation and transmission unit thatsequentially generates the two-dimensional images and transmits thegenerated two-dimensional image to the user terminal, based on thecalculated secondary display control information.
 2. The imageprocessing device according to claim 1, wherein the information of theinterest region is stored in the storage unit in advance and includesthe degree of interest which represents levels of suspicion aboutdisease in an imaging region corresponding to the interest region. 3.The image processing device according to claim 1, wherein the primarydisplay control information includes information representing aninterval between continuous input signals from the user terminal.
 4. Theimage processing device according to claim 3, wherein the informationrepresenting the interval between the continuous input signals from theuser terminal in the primary display control information includesinformation representing a length of time from a previous input to acurrent input, which is related to cumulative time of each of thecontinuous inputs in the continuous inputs in which the inputs signalsare continuously input with the interval which is equal to or greaterthan a predetermined number of less than a predetermined time.
 5. Theimage processing device according to claim 1, wherein the primarydisplay control information includes an input number per unit time. 6.The image processing device according to claim 1, wherein the secondarydisplay control information includes a time interval from an input timeof the input signal to a display time of the two-dimensional image. 7.The image processing device according to claim 1, wherein thetwo-dimensional image transmitted to the user terminal by the imagegeneration and transmission unit is a two-dimensional section imagewhich represents a section in a case where the three-dimensional imagewhich is an original image for generating the two-dimensional image iscut by a certain plane, and wherein the secondary display controlinformation includes position information of a section determining aposition in three dimensions of the plane.
 8. The image processingdevice according to claim 1, wherein the two-dimensional imagetransmitted to the user terminal in the image generation andtransmission unit is a three-dimensional visualization image which isreproduced by visualizing the three-dimensional image which is anoriginal image for generating the two-dimensional image to a state whenviewed from a certain viewpoint in three dimensions, and wherein thesecondary display control information includes the position informationof the viewpoint when the three-dimensional visualization image isgenerated or information of a resolution when the three-dimensionalvisualization image is generated.
 9. The image processing deviceaccording to claim 3, wherein the primary display control informationincludes certain input speed which is an inverse number of the timeinterval of the continuous input signals.
 10. The image processingdevice according to claim 1, wherein the primary display controlinformation is input speed which is an inverse number of the timeinterval of the continuous input signals, and wherein the storage unitfurther stores the primary display control information, the secondarydisplay control information, the information of the interest region, anda table that has any one value in two values of small and large bycombination of each parameter, in which the time interval between theinput time and the display time is described by parameterizing twovalues of large and small for the degree of interest of the interestregion, two values of which one value is equal to or greater than afirst threshold and the other value is less than the first threshold forthe input speed, and two values of which one value is equal to orgreater than a second threshold and the other value is less than thesecond threshold for a change flag which indicates the number of timesof the input speed falling below the first threshold, respectively, andwherein in the table, the time interval is described to have the largevalue only in a case where the degree of interest has the large value,the input speed has the value which is equal to or greater than thefirst threshold, and the change flag has the value which is less thanthe second threshold, the time interval has a small value in a casewhere the degree of interest has the small value, the input speed hasthe value which is equal to or greater than the first threshold, and thechange flag has the value which is less than the second threshold when auser starts image interpretation from the outside of the interestregion, and in a case where the user does not reduce imageinterpretation speed even when entering the interest region, the displayspeed of the two-dimensional image is delayed by the degree of interesthaving the large value, the input speed having the value which is equalto or greater than the first threshold, and the change flag having thevalue which is less than the second threshold and thus the time intervalhaving the large value.
 11. An image processing system which comprisesan image processing device and a user terminal connected to the imageprocessing device, the image processing device, including: a storageunit that stores an image database relating to a three-dimensionalimage; an input receiving unit that receives an input signal accordingto an operation of the user terminal; a primary display controlinformation calculating unit that calculates primary display controlinformation including a speed of the received input signal; a secondarydisplay control information calculating unit that calculates secondarydisplay control information including a display speed of atwo-dimensional image which is generated from the three-dimensionalimage based on information of an interest region determined as a highsuspicion disease region in the three-dimensional image and thecalculated primary display control information; and an image generationand transmission unit that sequentially generates the two-dimensionalimages and transmits the generated two-dimensional image to the userterminal, based on the calculated secondary display control information.12. An image processing method which generates and displays atwo-dimensional image from a three-dimensional image, the methodcomprising: a step of receiving an input signal regarding primarydisplay control information including a speed of a display control inputof the two-dimensional image from an input unit; an input step ofreceiving an input signal according to an operation of an input devicefrom each input unit; a step of calculating the primary display controlinformation including a speed of the received input signal; a step ofcalculating secondary display control information including a displayspeed of the two-dimensional image based on information of an interestregion stored in a storage unit in advance and the primary displaycontrol information; and an image generation and transmission step ofsequentially generating the two-dimensional image based on the secondarydisplay control information and displaying the generated two-dimensionalimage in the display unit.